Pakistan Army, however, ruled out the possibility of any terrorist or subversive activity in the crash in Pakistan- occupied Kashmir's Gilgit-Baltistan in the north.
Leif H Larsen, the Norwegian envoy, and Domingo D Lucenario Jr of the Philippines were killed along with the wives of the Malaysian and Indonesian ambassadors, besides two army pilots in the helicopter that caught fire as it crashed into a school that had children inside at the time.
"Two pilots and four foreigners, including ambassadors of Philippine, Norway and wives of Malaysian and Indonesian ambassador were killed," military spokesman Major General Asim Saleem Bajwa said.
"Update Naltar:2 pilots,4 foreigners fatalities.(Ambs Philippine, Norway,wives of Malaysian& Indonesian Ambs).Injured-Polish&Dutch Ambs-5," tweeted Bajwa.
More From This Section
Polish ambassador Andrzej Ananiczolish and Dutch ambassador Marcel de Vink were also injured in the crash.
Bajwa said that three Mi-17 military helicopters were carrying several diplomats to Gilgit-Baltistan in Pakistan- occupied Kashmir (PoK) where Sharif was to address a ceremony.
"The helicopter was shot down by an anti-aircraft missile, killing pilots and many foreign ambassadors," according to a statement in Urdu emailed by the TTP's main spokesman Muhammad Khorasani.
"A special group of Tehreek-e-Taliban Pakistan had prepared a special plan to target Nawaz Sharif during his visit but he survived because he was travelling in another helicopter," Khorasani added.
The TTP claim could not be immediately verified, but the Gilgit-Baltistan region is not known to be a stronghold for the militant outfit.